Graphium levassori

IUCN Red List conservation status: Endangered

Graphium levassori, which has no common name, is confined to Grande Comore in the Comoro Islands, where it is extremely scarce. There is no information on its biology or ecology and surveys and studies are urgently needed.

Description

This pale yellow butterfly with black markings is in the leonidas group (4) and has similar sexes, though the females are slightly larger (Plate 2.5). The forewing length is 43-55 mm (3, 7). The upper forewing is pale yellow with a black apex, outer and costal margins; wing base reddish with a small black cell spot, two yellow apical spots and a narrow yellow streak between the cell and the outer margin (3, 6). The upper hindwing is also pale yellow, with a black border to the scalloped outer margin. There is some brown scaling at the apex with two yellow lunules and a silvery-white costal margin (3, 6, 7).The lower forewing and lower hindwing differs from the uppersides in having fawn instead of black scaling and brick-red wing base (3, 6, 7).

Distribution

This species is endemic to Grande Comore in the Comoro Islands, between Mozambique, on the African mainland, and Madagascar in the Indian Ocean (3,6).

The four islands of the Comoros are volcanic in origin, Grande Comore being the most recent. On Grand Comore there are two uplifted areas, the volcanic massif of La Grille (1087 m) in the north, and the still active volcano of Karthala (2560 m) in the south. All the islands are characterized by moderate rainfall (1000-5000 mm per year) and soils with a very poor capacity for water retention. There are no streams or rivers on Grande Comoro, although subterranean hollows in the lava may hold water and encourage growth of forest (9). Patches of forest may still be found at low and middle altitudes e.g. near Nioumbadjou (550 m), but the main forests occur on the flanks of La Grille and Karthala up to a maximum of 1900 m (1 ). The forests on La Grille have been severely depleted by banana cultivation, but they are more extensive on Karthala, on whose western and south-western sides forest may grow at altitudes as low as 550-800 m (1 )

Graphium levassori inhabits forested areas and is believed to be very local in its distribution (5). In 1980 it was reported from forests near M’Lima Manda, north of Karthala, where it was said to be not rare and difficult to capture (9). However, a further visit to search for the butterfly in 1983 was unsuccessful (8). Little is known of the habits or biology of this species, but other members of the leonidas group feed on Annonaceae, the Custard Apple family (4). G. levassori has been found at sea level in the north of the island, where the cultivated Custard Apple (Annona reticulata) is common (2), but this seems to be an exceptional record and has not been recently confirmed. The adults may be on the wing all year round since dry periods are not usually prolonged, but they are certainly on the wing at the beginning of the heaviest rains in April (9).

Threats

Graphium levassori is one of many species of insects and other organisms, including Papilio aristophontes, that are confined to the forests of Grande Comore and the other Comoro Islands. Even within these forests G. levassori seems to be restricted to medium altitudes and very patchily distributed. There is considerable evidence that the forests are under increasingly severe pressure and that if forest destruction continues to accelerate, extinctions are inevitable.

The estimated human population of Grande Comore in 1976 was 150 000, and growing rapidly. The island is mainly farmed at the subsistence level and income from the main cash crops such as vanilla, copra, cacao, sisal, coffee, cloves and essential oils is very low. The main subsistence crop is bananas, plantations and gardens of which clothe the island. Even forests on La Grille and Karthala, from a distance apparently dense and healthy, may be found on closer inspection to include few large trees and a dense understorey of banana trees (9). The wild trees are unable to reproduce and regenerate, and they are gradually retreating higher and higher (9). Bananas are grown at altitudes up to 1200 m; the destruction is particularly serious on La Grille, but also extensive on Karthala (1, 9). The gradual erosion of the forests by the planting of bananas has been continuing for at least the past 25 years (9).

Conservation Measures

Even though Graphium levassori may be able to eke out an existence on cultivated Custard Apple, the only way to ensure its long-term survival is protection of its forest home from the constant incursion of banana growers. At present there are no protected areas on the islands, a situation which should be remedied as soon as possible. It is clearly necessary to create a series of reserves in representative biotopes. In the middle altitudes of Karthala it is almost too late to find undisturbed forest, but some areas should be protected and allowed to regenerate. At higher altitudes of 1200 m and above, the government could consider making the whole of Karthala a protected area. This would not affect many people and would ensure the survival of at least the higher altitude species for posterity.

Conservation measures specifically for Graphium levassori are not possible at this stage. More data are needed on its distribution and ecology in order that measures for its protection may be incorporated into efforts to conserve representative biotopes. Being large and spectacular as well as rare, Graphium levassori is prized by collectors (5). A farming or ranching programme on Custard Apple bushes could be developed into a useful local industry as well as a valuable measure for conservation purposes.

This page has been transcribed and edited, with permission, from Threatened Swallowtail Butterflies of the World: the IUCN Red Data Book by N.M. Collins & M.G. Morris. Whilst providing a sound baseline of information, it is in need of updating. The full volume, with references, may be downloaded from the IUCN Library System.

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